Do you have any other sound cards or onboard sound?
If so you need to tell jackd which soundcard to use,
eg. jackd -R -P80 -d alsa -d hw:1
tells it to use the second sound card (hw:0 is the first card and is the default).
You also need to tell envy24control which card to use,
eg. envy24control -c1
tells it to use the second card (-c0 is the first and is the default). You should read the man pages:
man envy24control
man jackd

In qjackctl, go to the setup page and make sure the delta1010 is configured as the right soundcard. Save the configuration and close the setup page. Then make sure you've pressed the "Start" button in qjackctl (the one labeled "Start", not the play button below the status display).

If and when the status display says "Started" on the top left hand corner, check the connections window and look at the available audio ports.